1. Field of the Invention
The present invention relates to indexing elements for controlling the sequence of operation of a chronometer-controlled device, and in particular to such an indexing element which is selectively programmable for actuating a switch means in the chronometer.
2. Description of the Prior Art
An indexing element in the form of a disc, particularly for use in switch clocks, is disclosed in German OS No. 2,813,069. The indexing disc disclosed therein is manufactured from thermoplastic material by injection molding and exhibits cam-like switch fingers connected to the indexing disc in the form of thin lamellae so as to form a one-piece structure. In order to program the indexing disc, the fingers are pressed axially behind an annular retaining edge of the indexing disc against a restoring force resulting from the elastic spring characteristics of the lamellae. Depression of a selected finger causes actuation of electrical contacts of a stationary switch means as the disc is rotated.
The conventional indexing disc described in German OS No. 2,813,069 has the disadvantage of requiring relatively involved tooling steps for manufacturing the disc. Moreover, the economically attainable width or division of the individual switch fingers, which determines the minimum chronological graduation between two switch instructions relative to one another, are relatively large such that the minimum time unit division available for programming is relatively large and is thus frequently not sufficiently fine to satisfy operating requirements.